Although it's just a game, the designers seem to be dedicated to making the game as movie-realistic as possible. Which makes these three entries interesting, in respect to what we already know, and ties to prequel backstory. My speculation is that these three planets will join Coruscant and Tatooine as the five planets of Episode III.

Naboo:

The Emperor has erected a stunning retreat on his home planet where he holds summits with high-ranking Imperial personnel. Imperial sympathizers can find a wide range of adventures here to pull them headlong into the throes of the Galactic Civil War. Perhaps after many trials and successful missions on behalf of the Empire, the most skilled agents may even gain an audience with the Emperor himself.

Lok:

Lok has fairly varied terrain, ranging from the dangerous sulfur pools to bubbling lava pits. The landscapes are generally foreboding: jagged mountain ranges, long expanses of baked desert, and desolate flats are typical environments on Lok. The presence of pirates and others is evident in the shipwrecks, burned-out bases, abandoned settlements, and destroyed vehicles that litter the planet.

Correlia

Although Corellia has never appeared in any of the Star Wars films, it's a key location in the greater Star Wars saga. Most notably, Corellia is Han Solo's homeworld. Other Corellian native sons include Rebel general Crix Madine, outspoken senator Garm Bel Iblis, and Rogue Squadron's Corran Horn. Corellia also witnessed the birth of the Rebel Alliance when senators Mon Mothma, Garm Bel Iblis, and Bail Organa vowed to overthrow senator Palpatine and signed the so-called Corellian Treaty, which officially founded the Rebel Alliance.